1. Field of the Invention
The present invention relates to a method of performing surface treatment on parts of large dimensions, in particular motor vehicle bodywork parts, and to a parts gripper that is adapted to implement such a method.
2. Description of the Related Art
Bodywork parts are usually painted by locally spraying paint in the form of droplets or solid particles onto the parts for painting, which parts are carried by moving supports that travel past paint spray stations while presenting the parts in a constant orientation that is appropriate for their treatment. In other words, the parts are moved in translation during painting operations, and while they are passing from one paint station to a following station, robots or operators sweep the local paint spray nozzles over the parts that are moving in translation.
That method, which has been practiced for several years, is considered as being optimal and has been adopted almost unanimously in the industry.
Nevertheless, although it provides high-quality results, it gives rise to small imperfections. At present, those small imperfections are not considered as being troublesome, however ever-increasing expectations in terms of quality may lead to requirements being increased in the future.
In the present description, the term “surface treatment” is used to mean any step in an overall method for treating the surface of a part. The overall method may consist in painting the part, in which case potential surface treatment methods are cleaning (by air-blast or cryogenically), flame scarfing, applying a primary, applying a color base, applying a varnish, or finishing treatment without paint, such as applying only varnish, or indeed performing quality control on the part, in which case the local treatment consists in scanning predefined portions of the part in order to send images to an image analyzer device, or indeed positioning a gasket or a bead of adhesive along a predetermined path.
In order to perform the above surface treatment, a local treatment device is used, e.g. a camera for a quality-control method or a paint spray nozzle for applying paint to the part.
The present invention seeks to propose a novel surface treatment method that further improves the quality of the treatment and/or of the parts obtained thereby, while in parallel also providing other advantages in industrial terms.